The field of the invention generally relates to automatic washing machines, and more particularly relates to rinse aid dispensers for such automatic washing machines.
As is well known, it may be desirable to add a liquid rinse aid such as a fabric softener or an anti-cling agent to the rinse water. Accordingly, many automatic washing machines include a rinse aid dispenser that introduces the rinse aid at the beginning of the rinse cycle. In the typical arrangement, the rinse aid dispenser mounts on the top of the agitator post, and the rinse aid is poured into a generally cone-shaped interior cup that holds the rinse aid during the wash/agitate cycle. During the spin cycle, centrifugal force causes the liquid rinse aid to spray up and out of the cup, and the centrifugal force retains the rinse aid against the interior wall of a cylindrical housing that surrounds the cup. When the spinning stops, the rinse aid drains down a funnel into a chamber of the agitator post from where it enters the spin basket through one or more slots in the post.
The above described arrangement generally operates effectively under the normal conditions when the spin axis is substantially vertical However, problems may occur if there is an unbalanced or out-of-balance wash load such that the agitator post and the dispenser orbit about the vertical axis. One problem is that rather than being uniformly spread around the interior wall of the housing after leaving the cup, the orbiting cause the rinse aid to congregate in an angular region such as a 90.degree. quadrant. As a result, the normal height of the rinse aid increases on the wall of the housing, and the rinse aid can be forced over the top of the cup and back out the fill hole. Such operation is undesirable because the rinse aid can stain the clothes if it sprays outwardly on them in its concentrated form. The concentrated rinse aid can also stain the clothes as a result of another problem associated with out-of-balance orbiting. More specifically, during spin acceleration at or near critical spin speed (e.g. 250 rpm) before the spin acceleration mass effectively reduces the orbiting distance, the orbiting may be so extreme that the rinse aid is not effectively held against the housing wall by centrifugal force, and some may drain prematurely down through the drain hole in the funnel. Then, by centrifugal force during high speed spin, the concentrated rinse aid can be sprayed out through the slot onto the clothes.
Further, staining of the clothes can also result if some of the rinse aid leaves the cup and passes into the housing prematurely during the wash/agitate cycle. Such operation can generally result from two different conditions. First, the rapid back and forth motion of the agitator post during agitation can cause wave action in the rinse aid in the cup thus causing the rinse aid to splash out over the rim. Second, the rinse aid can be siphoned out of the cup by a negative pressure within the housing caused by the rise and fall of wash water in the agitator chamber within the agitator as created by the back and forth oscillation of the agitator.
Further, staining of the spin dried wash clothes can occur as rinse aid residue drains off the interior walls of the dispenser into the agitator chamber and out the slots into the wash load.
The above described rinse aid dispensers have been made in large and compact sizes. The above-described clothes staining problems are improved (i.e. not so severe) with large dispensers due to a number of reasons. For example, there is more volume in the housing so it is less likely that the rinse aid will spray out of the fill hole. Also, the centrifugal force is greater with a large dispenser, so it is less likely that the centrifugal force will not be large enough to prevent the rinse aid from prematurely draining out the bottom. Further, with a large dispenser, the holding cup can be made larger so the rinse aid can be diluted. Thus, its staining tendency is reduced, and also diluted rinse aid is less likely to accumulate on the interior of the dispenser and drip down at a later time. However, one serious drawback of a large dispenser is that it limits the access opening to the clothes basket for loading and unloading clothes.